Hard & Sore knot under big toe

Hi,
I have a hard and sore knot under my big toe, kind of close to where the toe bends…and to the right.
It hurts when I press on it and when I walk.
It almost feels like I’m pressing on bone.
I am a 30 year old female and I weigh 140 pounds at 5’6″.
I do wear heels…because I have to dress nice at work.
What do you think it is and what can I do to alleviate the pain?
Thanks in advance